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add support for special values NotaNumber, MinusZero

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hexcoder-
2021-12-10 22:58:44 +01:00
parent 6ce72deb75
commit 82f1cf0735
1 changed files with 115 additions and 24 deletions
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139
instrumentation/split-compares-pass.so.cc
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@ -882,6 +882,7 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
// BUG FIXME TODO: u64 does not work for > 64 bit ... e.g. 80 and 128 bit // BUG FIXME TODO: u64 does not work for > 64 bit ... e.g. 80 and 128 bit
if (sizeInBits > 64) { continue; } if (sizeInBits > 64) { continue; }
IntegerType *intType = IntegerType::get(C, op_size);
const unsigned int precision = sizeInBits == 32 ? 24 const unsigned int precision = sizeInBits == 32 ? 24
: sizeInBits == 64 ? 53 : sizeInBits == 64 ? 53
: sizeInBits == 128 ? 113 : sizeInBits == 128 ? 113
@ -913,14 +914,99 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
BasicBlock *end_bb = bb->splitBasicBlock(BasicBlock::iterator(FcmpInst)); BasicBlock *end_bb = bb->splitBasicBlock(BasicBlock::iterator(FcmpInst));
/* create the integers from floats directly */ /* create the integers from floats directly */
Instruction *b_op0, *b_op1; Instruction *bpre_op0, *bpre_op1;
b_op0 = CastInst::Create(Instruction::BitCast, op0, bpre_op0 = CastInst::Create(Instruction::BitCast, op0,
IntegerType::get(C, op_size)); IntegerType::get(C, op_size));
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), b_op0); bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), bpre_op0);
b_op1 = CastInst::Create(Instruction::BitCast, op1, bpre_op1 = CastInst::Create(Instruction::BitCast, op1,
IntegerType::get(C, op_size)); IntegerType::get(C, op_size));
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), b_op1); bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), bpre_op1);
/* Check if any operand is NaN.
* If so, all comparisons except unequal (which yields true) yield false */
/* build mask for NaN */
const unsigned long long NaN_lowend = mask_exponent << precision;
// errs() << "Fractions: IntFractionTy size " <<
// IntFractionTy->getPrimitiveSizeInBits() << ", op_size " << op_size <<
// ", mask_fraction 0x";
// errs().write_hex(mask_fraction);
// errs() << ", precision " << precision <<
// ", NaN_lowend 0x";
// errs().write_hex(NaN_lowend); errs() << "\n";
/* Check op0 for NaN */
/* Shift left 1 Bit, ignore sign bit */
Instruction *nan_op0, *nan_op1;
nan_op0 = BinaryOperator::Create(
Instruction::Shl, bpre_op0,
ConstantInt::get(bpre_op0->getType(), 1));
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), nan_op0);
/* compare to NaN interval */
Instruction *is_op0_nan =
CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_UGT, nan_op0, ConstantInt::get(intType, NaN_lowend) );
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()),
is_op0_nan);
/* Check op1 for NaN */
/* Shift right 1 Bit, ignore sign bit */
nan_op1 = BinaryOperator::Create(
Instruction::Shl, bpre_op1,
ConstantInt::get(bpre_op1->getType(), 1));
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), nan_op1);
/* compare to NaN interval */
Instruction *is_op1_nan =
CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_UGT, nan_op1, ConstantInt::get(intType, NaN_lowend) );
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()),
is_op1_nan);
/* combine checks */
Instruction *is_nan = BinaryOperator::Create(
Instruction::Or, is_op0_nan, is_op1_nan);
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()),
is_nan);
/* the result of the comparison, when at least one op is NaN
is true only for the "NOT EQUAL" predicates. */
bool NaNcmp_result =
FcmpInst->getPredicate() == CmpInst::FCMP_ONE ||
FcmpInst->getPredicate() == CmpInst::FCMP_UNE;
BasicBlock *nonan_bb =
BasicBlock::Create(C, "noNaN", end_bb->getParent(), end_bb);
BranchInst::Create(end_bb, nonan_bb);
auto term = bb->getTerminator();
/* if no operand is NaN goto nonan_bb else to handleNaN_bb */
BranchInst::Create(end_bb, nonan_bb, is_nan, bb);
term->eraseFromParent();
/*** now working in nonan_bb ***/
/* Treat -0.0 as equal to +0.0, that is for -0.0 make it +0.0 */
Instruction *b_op0, *b_op1;
Instruction *isMzero_op0, *isMzero_op1;
const unsigned long long MinusZero = 1UL << (sizeInBits - 1U);
const unsigned long long PlusZero = 0;
isMzero_op0 =
CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, bpre_op0, ConstantInt::get(intType, MinusZero));
nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), isMzero_op0);
isMzero_op1 =
CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, bpre_op1, ConstantInt::get(intType, MinusZero));
nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), isMzero_op1);
b_op0 = SelectInst::Create(isMzero_op0, ConstantInt::get(intType, PlusZero), bpre_op0);
nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), b_op0);
b_op1 = SelectInst::Create(isMzero_op1, ConstantInt::get(intType, PlusZero), bpre_op1);
nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), b_op1);
/* isolate signs of value of floating point type */ /* isolate signs of value of floating point type */
@ -931,21 +1017,21 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
s_s0 = s_s0 =
BinaryOperator::Create(Instruction::LShr, b_op0, BinaryOperator::Create(Instruction::LShr, b_op0,
ConstantInt::get(b_op0->getType(), op_size - 1)); ConstantInt::get(b_op0->getType(), op_size - 1));
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), s_s0); nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), s_s0);
t_s0 = new TruncInst(s_s0, Int1Ty); t_s0 = new TruncInst(s_s0, Int1Ty);
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), t_s0); nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), t_s0);
s_s1 = s_s1 =
BinaryOperator::Create(Instruction::LShr, b_op1, BinaryOperator::Create(Instruction::LShr, b_op1,
ConstantInt::get(b_op1->getType(), op_size - 1)); ConstantInt::get(b_op1->getType(), op_size - 1));
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), s_s1); nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), s_s1);
t_s1 = new TruncInst(s_s1, Int1Ty); t_s1 = new TruncInst(s_s1, Int1Ty);
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), t_s1); nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()), t_s1);
/* compare of the sign bits */ /* compare of the sign bits */
icmp_sign_bit = icmp_sign_bit =
CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, t_s0, t_s1); CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, t_s0, t_s1);
bb->getInstList().insert(BasicBlock::iterator(bb->getTerminator()), nonan_bb->getInstList().insert(BasicBlock::iterator(nonan_bb->getTerminator()),
icmp_sign_bit); icmp_sign_bit);
/* create a new basic block which is executed if the signedness bits are /* create a new basic block which is executed if the signedness bits are
@ -962,9 +1048,9 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
BranchInst::Create(end_bb, middle_bb); BranchInst::Create(end_bb, middle_bb);
auto term = bb->getTerminator(); term = nonan_bb->getTerminator();
/* if the signs are different goto end_bb else to signequal_bb */ /* if the signs are different goto end_bb else to signequal_bb */
BranchInst::Create(signequal_bb, end_bb, icmp_sign_bit, bb); BranchInst::Create(signequal_bb, end_bb, icmp_sign_bit, nonan_bb);
term->eraseFromParent(); term->eraseFromParent();
/* insert code for equal signs */ /* insert code for equal signs */
@ -1261,7 +1347,7 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
} }
PHINode *PN = PHINode::Create(Int1Ty, 3, ""); PHINode *PN = PHINode::Create(Int1Ty, 4, "");
switch (FcmpInst->getPredicate()) { switch (FcmpInst->getPredicate()) {
@ -1269,37 +1355,45 @@ size_t SplitComparesTransform::splitFPCompares(Module &M) {
case CmpInst::FCMP_OEQ: case CmpInst::FCMP_OEQ:
/* unequal signs cannot be equal values */ /* unequal signs cannot be equal values */
/* goto false branch */ /* goto false branch */
PN->addIncoming(ConstantInt::get(Int1Ty, 0), bb); PN->addIncoming(ConstantInt::get(Int1Ty, 0), nonan_bb);
/* unequal exponents cannot be equal values, too */ /* unequal exponents cannot be equal values, too */
PN->addIncoming(ConstantInt::get(Int1Ty, 0), signequal_bb); PN->addIncoming(ConstantInt::get(Int1Ty, 0), signequal_bb);
/* fractions comparison */ /* fractions comparison */
PN->addIncoming(icmp_fraction_result, middle2_bb); PN->addIncoming(icmp_fraction_result, middle2_bb);
/* NaNs */
PN->addIncoming(ConstantInt::get(Int1Ty, NaNcmp_result), bb);
break; break;
case CmpInst::FCMP_ONE: case CmpInst::FCMP_ONE:
case CmpInst::FCMP_UNE: case CmpInst::FCMP_UNE:
/* unequal signs are unequal values */ /* unequal signs are unequal values */
/* goto true branch */ /* goto true branch */
PN->addIncoming(ConstantInt::get(Int1Ty, 1), bb); PN->addIncoming(ConstantInt::get(Int1Ty, 1), nonan_bb);
/* unequal exponents are unequal values, too */ /* unequal exponents are unequal values, too */
PN->addIncoming(icmp_exponent_result, signequal_bb); PN->addIncoming(icmp_exponent_result, signequal_bb);
/* fractions comparison */ /* fractions comparison */
PN->addIncoming(icmp_fraction_result, middle2_bb); PN->addIncoming(icmp_fraction_result, middle2_bb);
/* NaNs */
PN->addIncoming(ConstantInt::get(Int1Ty, NaNcmp_result), bb);
break; break;
case CmpInst::FCMP_OGT: case CmpInst::FCMP_OGT:
case CmpInst::FCMP_UGT: case CmpInst::FCMP_UGT:
/* if op1 is negative goto true branch, /* if op1 is negative goto true branch,
else go on comparing */ else go on comparing */
PN->addIncoming(t_s1, bb); PN->addIncoming(t_s1, nonan_bb);
PN->addIncoming(icmp_exponent_result, signequal2_bb); PN->addIncoming(icmp_exponent_result, signequal2_bb);
PN->addIncoming(PN2, middle2_bb); PN->addIncoming(PN2, middle2_bb);
/* NaNs */
PN->addIncoming(ConstantInt::get(Int1Ty, NaNcmp_result), bb);
break; break;
case CmpInst::FCMP_OLT: case CmpInst::FCMP_OLT:
case CmpInst::FCMP_ULT: case CmpInst::FCMP_ULT:
/* if op0 is negative goto true branch, /* if op0 is negative goto true branch,
else go on comparing */ else go on comparing */
PN->addIncoming(t_s0, bb); PN->addIncoming(t_s0, nonan_bb);
PN->addIncoming(icmp_exponent_result, signequal2_bb); PN->addIncoming(icmp_exponent_result, signequal2_bb);
PN->addIncoming(PN2, middle2_bb); PN->addIncoming(PN2, middle2_bb);
/* NaNs */
PN->addIncoming(ConstantInt::get(Int1Ty, NaNcmp_result), bb);
break; break;
default: default:
continue; continue;
@ -1341,18 +1435,15 @@ bool SplitComparesTransform::runOnModule(Module &M) {
if (enableFPSplit) { if (enableFPSplit) {
simplifyFPCompares(M);
count = splitFPCompares(M); count = splitFPCompares(M);
/* if (!be_quiet && !debug) {
if (!be_quiet) {
errs() << "Split-floatingpoint-compare-pass: " << count errs() << "Split-floatingpoint-compare-pass: " << count
<< " FP comparisons split\n"; << " FP comparisons splitted\n";
} }
*/
simplifyFPCompares(M);
} }